As device densities decrease, new developments in the design of semiconductor and other electronic devices receive continued focus. Advances in semiconductor processing and device design have resulted in computing devices being incorporated in a vast variety of machines, ranging from conventional programmable computers, and personal electronic equipment such as cell phones a PDAs to large scale communications systems, among others. There is an un-exhaustive demand for smaller, smarter devices that continue to offer more memory and functionality.
To meet such extensive demands, memory devices implement hundreds of megabits of storage in a single integrated circuit. These devices include volatile memory such as dynamic random access memory (DRAM) and static random access memory (SRAM), non-volatile memory such as electrically erasable programmable read only memory (EEPROM), flash RAM, ferroelectric DRAM), among others. Production of such memory devices continues to push the limits of processes and manufacturing equipment.
Performance of the memory components of a computing device is becoming an increasingly important determinant of overall system performance. Larger quantities of memory enable a greater variety of applications and functions to be implemented by the computing device and may reduce or eliminate the need for separate mass storage devices. Higher speed memory supports higher CPU processing frequencies, making the computing devices more useful for complex or real-time tasks. Denser memory devices support a growing variety of battery-powered electronic devices, such as laptop computers, PDAs, multifunction cellular telephones, and the like. At the same time, many of these applications benefit from reduced power consumption.
In many cases, improvements in semiconductor processing technology have led to the manufacture of denser, larger, faster and more power efficient memory devices. In many cases, the solid-state electronic behavior of the devices improves as the devices become smaller. Unfortunately, conventional memory, such as silicon-based DRAM memory, has reached a point where continued reduction in the size of conventional semiconductor memory cells is expected to adversely affect at least some of these important parameters.
One potential way to continue the development of ever faster, denser and more efficient devices is to develop molecular devices that implement some or all components of an electronic device or system with molecular scale structures and components. These molecular scale structures and components exhibit molecular rather than solid-state behavior. This can provide enhanced performance of the devices in many instances and permit further developments in device design. Molecules retain their essential properties down to the individual molecule level, and thus molecular-scale components and device structures can continue to be scaled down as future technologies and device designs develop.
It is advantageous for molecular device manufacturing techniques to be compatible with existing semiconductor industry processes, and to use existing semiconductor industry techniques and equipment were possible. However, molecular device processing is sensitive to many variables and conditions that are not problems in traditional semiconductor processing. Additionally, when devices are manufactured with molecular-scale features, problems are magnified and defects at the molecular scale become significant.
For example, in the fabrication of molecular memory devices, molecules are deposited onto a heterogeneous substrate having both conductive and non-conductive surfaces. Dissimilar surface tensions at these interfaces negatively impact the nucleation behavior of the molecules and the wetting behavior of a subsequently deposited charge transfer layer. This negatively impacts the ability to scale such structures. Further, such dissimilar nucleation and wetting behavior results in non-uniformities which degrade signal strength and speed performance, as well as negatively impact the reliability and reproducibility of the device. Thus, while developments have been made a continuing need exists for new developments in processing techniques and design of memory devices. Additionally, there is a need for continued advancements in molecular memory cells, molecular memory arrays, and electronic devices including molecular memory.